In bolting in narrow drifts in mines, there is often a conflict between the desired advance per round for the blast hole drilling and the feeding length in bolt drilling. If the required length for the blasting was to be drilled, the feeder would be so long that it would not be possible for it to be arranged transversely in the drift. One way of solving this problem is to use a feeder with displaceable drilling supports, another is to use a telescopic feeder. A telescopic feeder has a first beam and a second beam which is slidably arranged on the first beam. The length of the telescopic feeder may be changed so that it may be extended to the desired length in a drilling condition and retracted which results in that it may be accommodated transversely in the drift when needed.
An example of a telescopic feeder is disclosed in WO9518912. This telescopic feeder comprises a first beam and a second beam slidably arranged on the first beam. The disadvantage of this design is however that there are many slide blocks between the different moving parts of the telescopic feeder. Since the slide blocks have to be adjusted as they are worn, the maintenance work is greater on the telescopic feeder as compared to regular feeders. In particular, the adjustments of the slide blocks between the two beam profiles are difficult and time consuming to adjust correctly.